The increased ground clearance and diffuser implies a belly pan, to support clean, source flow, a dramatic departure from all previous NASCAR race cars.
And less rear spoiler is required with a diffuser in place. Free horsepower!
If lower overall drag is the result, NASCAR can impose restrictor-plates to limit power and top speeds. Speed kills. And this racing is about family entertainment.
Pit stops might still be governed by tire life, however, mpg may be impacted enough that 'fuel management' strategy becomes less critical for the teams.
Once, a rookie driver took the checkered flag, coasting through corners to conserve fuel, perhaps allowing for one less pitstop than other drivers. Something Danaka Patrick would later find to be a critical race strategy in Indycar racing.
